The lymphocytes were obtained from Down's syndrome patients and their parents' blood by Leuco PREP, subsequently, DNAs were extracted from lymphocytes using the Phenol-chloroform method. DNAs were digested with restriction enzyme and 10mug of digested DNAs were subjected to electrophoresis on 0.8% agarose gel. After electrophoresis, DNAs in the agarose gel were transfered to nitrocellulose (nylon) filter according to the method of Southern. Probes used were : D21S16, D21S17, D21S113,D21S15,D21S19 and D21S82, which were provided by JCRB. The probe was labeled with digoxigenin and hybridization was performed. ELISA method was used to detect DNAs.
Human gametes were investigated to determinate the causal factors and mechanisms of Down's syndrome chromosomal aberrations at the sometime as the parental origin of Down's syndrome was studied.
Two hundred and ninety seven infertilized human MI oocytes from IVF (in vitro fertilization) program were studied, using the technique of Mikamo and Kamiguchi. In the 297 oocytes, 148 (49.8%) were successfully karyotyped. The abnormal rats was 21% (32/148) among which 17.7% (26/148) were aneuploids consisting of 4.8% (7/148) hyperhaploidy, 4.8% (7/148) hypohaploidy and 8.1% (12/148) diploidy. The remaining 4.0% (6/148) showed structural anomalies. Only 0.68% (1/148) was observed to be G group chromosome abnormality that from the 4.8% (7/148) hyperhaploidy which may cause Down's syndrome.
Eighteen thousand human sperm from 6 healthy man were studied by FISH (fluorescence in situ hybridization) using specific alpha-satellite DNA probe D21Z1/D13Z1. Three thousand spots were counted for each slide. Three spots which indicate disomic sperm was about 0.71% for chromosome No.21 and 13, that means No.21 chromosome disomic rate was about 0.36%.